For some time now, many household appliances have been used and operate without being directly connected to an electric power source, such as, for instance, a conventional domestic electric power mains supply.
These household appliances, such as, for instance, vacuum cleaners, are technically called “cordless” household appliances.
In the specific case of vacuum cleaners, these essentially are composed of a casing inside which a motor is fitted that drives a fan that generates a vacuum, together with a filter for separating the impurities from the air sucked up by the fan and a set of batteries, normally of the rechargeable type, connected to the motor to drive it. When it is not used, or when the set of batteries is down, the vacuum cleaner is connected, by means of a specific cable, to a standard electric power mains socket, for instance an industrial or domestic mains supply, which recharges the set of batteries. When on the other hand, the vacuum cleaner is used, the domestic mains supply connection cable is disconnected to make it portable everywhere and the motor is driven by the set of batteries only.
Consequently, as long as the set of batteries has enough charge, the motor drives the fan which in turn generates vacuum, while when the charge is down, the motor stops driving the fan and the vacuum cleaner cannot be used until the batteries are recharged.
The set of batteries is often of the changeable type and, for this reason, users, to prevent the vacuum cleaner from stopping work before a cleaning cycle is over, purchase at least another set of spare batteries which is recharged by placing in a specific recharging apparatus connected to the power mains, while the first set is being used in the vacuum cleaner. This way, when the first set of batteries is down, this is removed from the vacuum cleaner and placed on the recharging apparatus and is substituted in the vacuum cleaner with the second charged set and the vacuum operation can be prolonged in time.
This state of the art does however have some drawbacks.
A first drawback is that the battery charge has a duration limited in time, above all in the event of the vacuum cleaner operation requiring high motor powers and, consequently, motor operation that is always close to top rotation speed.
Another drawback is that users, so as not to have to interrupt use of the vacuum cleaner when a set of batteries is down, have to purchase, and keep at disposal, as has already been said, at least a second set of spare batteries to be recharged while the first set is being used, and vice versa.
Another drawback is that when the sets of batteries are no longer rechargeable and have to be replaced with other new ones because they have terminated their life cycle, these must be disposed of by depositing at places specifically dedicated to this purpose. Such disposal prevents, the pollution that would ensue if they were disposed of in places commonly set aside for the collection of domestic waste or, even worse, if they were abandoned in fields or thrown into water courses.
Another drawback is that the sets of batteries must have high charge capacities, which results in heavy weights and costs and requires long charging times that vary between three and five hours, during which time the portable household appliance is not usable.
Another drawback is that many types of battery sets cannot be completely recharged because, due to the material used to make them, these maintain a so-called “memory effect”, meaning that when they are no longer able to power the motor adequately, they are not completely discharged and maintain an albeit residual charge level which is not however usable.
When these sets of batteries undergo subsequent recharging, this only restores the difference in charge between the residual level and the maximum level. The upshot of this is that the duration of the usable charge is significantly reduced with respect to the real capacity of the battery sets.
The technical aim of the technology disclosed herein is to upgrade the state of the art.
An object of the technology disclosed herein is to make a portable household appliance, of the type without power cable, that has operating times considerably higher than those of a known portable household appliance.
Another object of the technology disclosed herein is to make a portable household appliance, of the type without power cable, that requires reduced recharge times.
Another object of the technology disclosed herein is to make a portable household appliance, of the type without power cable, that permits reducing the dimensions of power battery sets, maintaining performance levels substantially unchanged with respect to those of a known portable household appliance.
Another object of the technology disclosed herein is to make a portable household appliance, of the type without power cable that permits completing its operating function by recharging a motor power supply unit in a very short time, meaning in just a few seconds.